A: Yes and no. There are some guidelines that can be followed to make sure odd things don't happen. There have been times when a compressor after a delay pedal or reverb unit has caused some bad (good?) effects, there have been brilliant moves to place effects in certain orders that break most rules, but below is a guideline I came up with and was published in Musician's Hotline Magazine. Nice things is it gives you a way, a phrase to memorize so that when you're on the road, you can get it right if you pick up a new effect.
Placing effects in a logical order will help! This list of effects order is just a general guideline. Some of the best and most unique guitar tones have been created by breaking the rules! You guys need a head start at good tone right?! A way to make life easy right?! I came up with a little phrase to help remember the order because even I forget. Ask yourself this when you wonder about effects order or placement: Which Chain Of Effect Pedals Makes Life Easy? All you have to do is remember this phase and which letter corresponds to which type of effect. Wah -> Which, Compressor -> Chain, Overdrive -> Of, EQ -> Effect, Pitch -> Pedals, Modulation -> Make, Level -> Life, Echo -> Easy. I like to see wah pedals and sometimes even phasers as the first effect after the guitar. Well call these Wah effects (yes even the phaser). Wah pedals boost a frequency you sweep to with your foot and phasers cut or notch a frequency that is swept to electronically. Distortion pedals make interesting response changes to the boost or cut from these sweep pedals. Compressors typically go next although I like them after distortion pedals in many cases if the compressor is clean and transparent enough. Compression after distortion has two effects that I really like. First, the noise floor is lower because the noise from a compressor isnt being amplified and distorted by the overdrive pedal. Second, there appears to be more sustain. There is one draw back that some people notice and that is a darker, warmer tone. Some folks might prefer a more conventional, brighter tone. Next comes Overdrive or distortion. Equalizer pedals can go next. They are commonly used for a boost pedal if they can be turned on and off, or used to shape the tone of the distortion pedal. Pitch changing pedals, Vibrato for example; go next for the simple reason that many distortion pedals cant handle the many pitches at one time. Try strumming a complex chord with your distortion pedal on, say a C7#9#11. Modulation effects go next such as chorus and flanging go next. Level pedals that control the volume go next in many cases. This would include tremolo, volume pedals (great at this point in the effects chain because it cuts all the hiss going to your amp), noise gates and limiters. Since compression is a limiter in many cases and this is why it works post-distortion by the way. Echo effects go last. These include delay and reverb. A sample effects board might contain these effects: Guitar -> Wah, Compressor, Overdrive, EQ, Vibrato, Chorus, Tremolo, Volume Pedal, and Delay-> Amp. "